1. Field of the Invention
The present invention relates to an information processing apparatus such as a notebook personal computer (hereinafter referred to as a notebook PC). Particularly, the present invention relates to a casing structure of an information processing apparatus.
2. Description of Related Art
Nowadays, efforts have been made to improve the operating feeling of notebook PCs as the PCs are becoming multifunctional and their processing is becoming high-speed. As an effort to improve the operating feeling, for example, tactile feel upon depressing keys on a keyboard has been considered as important.
FIG. 8 illustrates an external view of a notebook PC as an example of a conventional information processing apparatus. As shown in FIG. 8, the notebook PC is configured of a first casing 101 provided with a keyboard 103, and a second casing 102 provided with a liquid crystal monitor 104. The first casing 101 and the second casing 102 are coupled pivotally by a hinge mechanism.
FIG. 9 is a cross-sectional view along a dash-dotted line portion X in FIG. 8. For clear illustration, a partial cross-sectional view is provided. In FIG. 9, illustration of various devices such as an electric circuit board, a central processing unit (CPU), and so on disposed in the first casing 101 is omitted. At the rear side of the keyboard 103, switches are disposed at positions corresponding to respective keys forming the keyboard 103, but illustrations of these are omitted. As shown in FIG. 9, the casing 101 is configured of an upper casing 101a and a lower casing 101b. The keyboard 103 is disposed on top of the upper casing 101a. The upper casing 101a on which the keyboard 103 is disposed is supported by some bosses and ribs (not shown) formed on the lower casing 101b. Keyboards with various structures are disclosed in Patent Document 1 (JP 2005-128610A), Patent Document 2 (JP H 6-12164A), Patent Document 3 (JP H 10-501649A), Patent Document 4 (JP H 8-110825A), and Patent Document 5 (JP H 11-345066A).
In many cases, in notebook PCs, their casings are formed thinly to reduce the weight. However, when the upper casing 101a shown in FIG. 9 is formed thinly and an operator depresses the keyboard 103 supported by the upper casing 101a with his/her fingers in the direction indicated by arrow Y, because there is no member to support the keyboard 103 and the upper casing 101a below the keyboard 103, the upper casing 101a is sinks down along with the keyboard 103, as shown in FIG. 10. Therefore, even if a click feeling is provided to each key forming the keyboard 103, since the upper casing 101a is sinks down upon operation using the keys, the click feeling of the keys is impaired.
Additionally, when the upper casing 101a is formed thinly, its strength decreases, and therefore upon application of a strong pressure to the surface thereof, the upper casing 101a flexes, which possibly may damage various components disposed inside the casing.